dialyzer: Warn for bad type variables of parameterized types
dialyzer: Warn for bad type variables of parameterized types

As of commit 854ee8b (Erlang/OTP 18) warnings about using '_' as type
variable in parameterized types have not been output.

The code of erl_types:t_var_names() is corrected. The spec is also
corrected (thanks to Kostis for pointing out the bug).

goertzenator/otp,tuncer/otp,kvakvs/otp,saleyn/otp,kvakvs/otp,fenollp/otp,ferd/otp,cobusc/otp,dumbbell/otp,goertzenator/otp,bsmr-erlang/otp,vinoski/otp,lrascao/otp,mikpe/otp,g-andrade/otp,legoscia/otp,vinoski/otp,dumbbell/otp,kvakvs/otp,bernardd/otp,potatosalad/otp,bernardd/otp,bjorng/otp,electricimp/otp,fenollp/otp,rlipscombe/otp,getong/otp,potatosalad/otp,bernardd/otp,vladdu/otp,RoadRunnr/otp,vladdu/otp,RaimoNiskanen/otp,bjorng/otp,goertzenator/otp,g-andrade/otp,uabboli/otp,cobusc/otp,isvilen/otp,uabboli/otp,mikpe/otp,mikpe/otp,potatosalad/otp,emacsmirror/erlang,isvilen/otp,falkevik/otp,erlang/otp,bjorng/otp,vinoski/otp,bsmr-erlang/otp,kvakvs/otp,saleyn/otp,vinoski/otp,dgud/otp,aboroska/otp,jj1bdx/otp,legoscia/otp,aboroska/otp,vladdu/otp,RaimoNiskanen/otp,isvilen/otp,falkevik/otp,dumbbell/otp,erlang/otp,dumbbell/otp,rlipscombe/otp,dgud/otp,RaimoNiskanen/otp,fenollp/otp,tuncer/otp,cobusc/otp,goertzenator/otp,erlang/otp,ferd/otp,falkevik/otp,isvilen/otp,isvilen/otp,isvilen/otp,fenollp/otp,g-andrade/otp,cobusc/otp,ferd/otp,RoadRunnr/otp,g-andrade/otp,getong/otp,jj1bdx/otp,lrascao/otp,mikpe/otp,electricimp/otp,kvakvs/otp,dgud/otp,RaimoNiskanen/otp,ferd/otp,RaimoNiskanen/otp,jj1bdx/otp,kvakvs/otp,aboroska/otp,mikpe/otp,dgud/otp,aboroska/otp,tuncer/otp,tuncer/otp,legoscia/otp,emacsmirror/erlang,jj1bdx/otp,matwey/otp,bsmr-erlang/otp,erlang/otp,vladdu/otp,matwey/otp,cobusc/otp,lrascao/otp,dgud/otp,vinoski/otp,matwey/otp,mikpe/otp,jj1bdx/otp,vladdu/otp,RaimoNiskanen/otp,bjorng/otp,legoscia/otp,vladdu/otp,potatosalad/otp,electricimp/otp,RoadRunnr/otp,falkevik/otp,fenollp/otp,legoscia/otp,dgud/otp,rlipscombe/otp,uabboli/otp,kvakvs/otp,vinoski/otp,bjorng/otp,emacsmirror/erlang,mikpe/otp,goertzenator/otp,erlang/otp,aboroska/otp,falkevik/otp,bernardd/otp,RaimoNiskanen/otp,goertzenator/otp,lrascao/otp,rlipscombe/otp,vladdu/otp,fenollp/otp,RoadRunnr/otp,isvilen/otp,fenollp/otp,cobusc/otp,vladdu/otp,falkevik/otp,saleyn/otp,rlipscombe/otp,bsmr-erlang/otp,dgud/otp,aboroska/otp,falkevik/otp,potatosalad/otp,RoadRunnr/otp,rlipscombe/otp,bernardd/otp,matwey/otp,emacsmirror/erlang,erlang/otp,lrascao/otp,getong/otp,getong/otp,tuncer/otp,emacsmirror/erlang,ferd/otp,getong/otp,uabboli/otp,uabboli/otp,kvakvs/otp,isvilen/otp,RaimoNiskanen/otp,bjorng/otp,potatosalad/otp,lrascao/otp,dgud/otp,vladdu/otp,emacsmirror/erlang,bjorng/otp,fenollp/otp,rlipscombe/otp,saleyn/otp,g-andrade/otp,dumbbell/otp,aboroska/otp,goertzenator/otp,rlipscombe/otp,saleyn/otp,electricimp/otp,bsmr-erlang/otp,isvilen/otp,lrascao/otp,dumbbell/otp,emacsmirror/erlang,ferd/otp,bernardd/otp,falkevik/otp,matwey/otp,saleyn/otp,RoadRunnr/otp,potatosalad/otp,mikpe/otp,erlang/otp,bsmr-erlang/otp,tuncer/otp,bernardd/otp,getong/otp,bjorng/otp,dgud/otp,matwey/otp,erlang/otp,dgud/otp,RoadRunnr/otp,erlang/otp,dumbbell/otp,electricimp/otp,jj1bdx/otp,matwey/otp,uabboli/otp,saleyn/otp,lrascao/otp,potatosalad/otp,dumbbell/otp,legoscia/otp,bsmr-erlang/otp,uabboli/otp,getong/otp,g-andrade/otp,fenollp/otp,saleyn/otp,emacsmirror/erlang,electricimp/otp,electricimp/otp,isvilen/otp,cobusc/otp,electricimp/otp,bsmr-erlang/otp,saleyn/otp,electricimp/otp,kvakvs/otp,getong/otp,jj1bdx/otp,jj1bdx/otp,tuncer/otp,getong/otp,cobusc/otp,matwey/otp,potatosalad/otp,ferd/otp,bjorng/otp,lrascao/otp,bjorng/otp,aboroska/otp,dumbbell/otp,legoscia/otp,potatosalad/otp,emacsmirror/erlang,goertzenator/otp,legoscia/otp,mikpe/otp,g-andrade/otp,legoscia/otp,erlang/otp,g-andrade/otp,ferd/otp,uabboli/otp,emacsmirror/erlang,jj1bdx/otp,tuncer/otp,bernardd/otp,uabboli/otp,g-andrade/otp,RoadRunnr/otp,jj1bdx/otp,getong/otp,vinoski/otp,rlipscombe/otp,ferd/otp,mikpe/otp,matwey/otp,RaimoNiskanen/otp,tuncer/otp,falkevik/otp,bernardd/otp,aboroska/otp,vinoski/otp,g-andrade/otp,goertzenator/otp,RoadRunnr/otp,bsmr-erlang/otp,rlipscombe/otp,dumbbell/otp,vinoski/otp,vinoski/otp